Cardiorespiratory fitness attenuates metabolic risk independent of abdominal subcutaneous and visceral fat in men

Cardiorespiratory fitness and submaximal exercise dynamics in normal-weight obesity and metabolically healthy obesity

PURPOSE

Cardiorespiratory fitness (CRF) is critical for cardiovascular health. Normal-weight obesity (NWO) and metabolically healthy obesity (MHO) may be at increased risk for cardiovascular disease, but a comparison of CRF and submaximal exercise dynamics against rigorously defined low- and high-risk groups is lacking.

METHODS

Four groups (N = 40; 10/group) based on body mass index (BMI), body fat %, and metabolic syndrome (MetS) risk factors were recruited: healthy controls (CON; BMI 18.5-24.9 kg/m2, body fat < 25% [M] or < 35% [F], 0-1 risk factors), NWO (BMI 18.5-24.9 kg/m2, body fat ≥ 25% [M] or ≥ 35% [F]), MHO (BMI > 30 kg/m2, body fat ≥ 25% [M] or ≥ 35% [F], 0-1 risk factors), or metabolically unhealthy obesity (MUO; BMI > 30 kg/m2, body fat ≥ 25% [M] or ≥ 35% [F], 2 + risk factors). All participants completed a V ˙ O2peak test on a cycle ergometer.

RESULTS

V ˙ O2peak was similarly low in NWO (27.0 ± 4.8 mL/kg/min), MHO (25.4 ± 6.7 mL/kg/min) and MUO (24.6 ± 10.0 mL/kg/min) relative to CON (44.2 ± 11.0 mL/kg/min) when normalized to total body mass (p's < 0.01), and adjusting for fat mass or lean mass did not alter these results. This same differential V ˙ O2 pattern was apparent beginning at 25% of the exercise test (PGroup*Time < 0.01).

CONCLUSIONS

NWO and MHO had similar peak and submaximal CRF to MUO, despite some favorable health traits. Our work adds clarity to the notion that excess adiposity hinders CRF across BMI categories.

CLINICALTRIALS

gov registration: NCT05008952.

Human cold adaptation: An unfinished agenda v2.0

BACKGROUND

Research on human extreme cold climate adaptations has benefitted from a recent resurgence since Ted Steegmann laid out his Human Cold Adaptation Agenda in 2007. Human biologists have drastically expanded our knowledge in this area during the last 15 years, but we still have a great deal more work to do to fulfill the cold climate adaptation agenda.

METHODS

Here, I follow Steegmann's example by providing a review of cold climate adaptations and setting forth a new, expanded agenda.

RESULTS

I review the foundational work on cold climate adaptations including classic Bergmann, Allen, and Thomson rules as well as early work assessing metabolic differences among Indigenous cold climate populations. From there, I discuss some of the groundbreaking work currently taking place on cold climate adaptations such as brown adipose tissue (a heat generating organ), physical activity levels, metabolic rates, and behavioral/cultural mechanisms. Finally, I present a path forward for future research with a focus on some of the basic extreme cold adaptations as well as how human biologists should approach the effects of climate change on human health and well-being, particularly within a cold climate context.

CONCLUSION

The Arctic has felt the dramatic effects of climate change sooner and more acutely than other parts of the world, making it an ideal location for studying both cold climate adaptations and climate change resilience. Human biologists have a great deal to contribute to the conversation on not only adaptations to extreme cold, but also the ways in which climate change is being embodied by cold climate populations.

Cardiorespiratory fitness and metabolic risk in Chinese population: evidence from a prospective cohort study

BACKGROUND

Studies on the association between estimated cardiorespiratory fitness (CRF) and changes in metabolic risk in the Chinese population are limited. This study aims to examine the associations between CRF and changes in metabolic risk.

SUBJECTS AND METHODS

We included 4,862 and 2,700 participants recruited from 28 provinces in the China Health and Retirement Longitudinal Study (CHARLS) in the baseline (Wave 1) and follow-up (Wave 4) analyses, respectively. CRF was calculated using sex-specific longitudinal non-exercise equations. Metabolic indicators included systolic blood pressure (SBP), diastolic blood pressure (DBP), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and fasting plasma glucose (FPG) levels. The metabolic score was calculated as the number of changes in the above metabolic indicators above the 75th percentile of the distribution of changes (equal to or below the 25th percentile for HDL-C).

RESULTS

In the baseline analysis, CRF was negatively associated with SBP, DBP, TG, and FPG, and positively correlated with HDL-C after adjusting for age, smoking status, and drinking status (all P < 0.0001) in both males and females. In the follow-up analysis, higher baseline CRF was significantly related to a decrease in SBP, DBP, TG, FPG, and metabolic score (all P < 0.0005), and increased HDL-C (P < 0.0001) after further adjustment for corresponding baseline metabolic indicators. The associations remained significant after stratification by sex, except for the changes in HDL-C levels in females. Furthermore, improved CRF was associated with favorable changes in DBP, TG, HDL-C, FPG, and metabolic scores in all populations and males. Significant associations between changes in CRF and DBP, TG, and FPG levels were found in females.

CONCLUSION

Higher baseline CRF and improved CRF were associated with favorable changes in metabolic indicators.

Effect of Short Bouts of Vigorous Stair Climbing on Cardiorespiratory Fitness in Women with Overweight and Obesity: A Pilot Feasibility Study

Background

We examined the effect of 4 weeks of a brief vigorous stair climbing exercise on cardiorespiratory fitness (CRF) and body composition in women with overweight or obesity.

Methods

Twenty-six participants (age, 25.4±4.9 years; body mass index [BMI], 25.3±1.8 kg/m2) were randomly assigned to either a stair climbing exercise group (n=13) or a non-exercising control group (n=13). The stair climbing exercise group performed 20 sessions (supervised, five sessions/week over 4 weeks) of brief intermittent stair climbing exercise consisting of a 3-minute warm-up followed by three bouts of 20 seconds of stair climbing (≥80% of age-predicted maximum heart rate) interspersed with 2-minute recovery periods (total exercise duration=10 minutes/session). Peak oxygen uptake (VO2peak) was measured using a graded maximal treadmill test with the use of a standard open-circuit spirometry technique. Body composition was assessed with bioelectrical impedance analysis.

Results

All participants, except one who dropped out due to coronavirus disease 2019 (COVID-19) infection, completed the study with 100% attendance rates. There were significant interaction effects (group×time) on body weight, BMI, waist circumference, and CRF such that the stair climbing exercise group had significant (P≤0.01) reductions in body weight (66.5±4.6 to 65.2±4.6 kg), BMI (24.8±1.2 to 24.4±1.1 kg/m2), and waist circumference (78.0±3.7 to 76.5±4.1 cm) and improvements in VO2peak (31.6±2.5 to 34.9±2.6 mL/kg/min) compared with controls.

Conclusion

Short bouts of vigorous stair climbing is a feasible and time-efficient exercise strategy for improving CRF in previously sedentary, young women with overweight and obesity.

Commentary-fat but fit…and cold? Potential evolutionary and environmental drivers of metabolically healthy obesity

As global obesity rates continue to rise, it is important to understand the origin, role and range of human variation of body mass index (BMI) in assessing health and healthcare. A growing body of evidence suggests that BMI is a poor indicator of health across populations, and that there may be a metabolically healthy obese phenotype. Here, we review the reasons why BMI is an inadequate tool for assessing cardiometabolic health. We then suggest that cold climate adaptations may also render BMI an uninformative metric. Underlying evolutionary and environmental drivers may allow for heat conserving larger body sizes without necessarily increasing metabolic health risks. However, there may also be a potential mismatch between modern obesogenic environments and adaptations to cold climates, highlighting the need to further investigate the potential for metabolically healthy obese phenotypes among circumpolar and other populations as well as the broader meaning for metabolic health.

Sex-Specific Relationship between the Cardiorespiratory Fitness and Plasma Metabolite Patterns in Healthy Humans-Results of the KarMeN Study

Cardiorespiratory fitness (CRF) represents a strong predictor of all-cause mortality and is strongly influenced by regular physical activity (PA). However, the biological mechanisms involved in the body's adaptation to PA remain to be fully elucidated. The aim of this study was to systematically examine the relationship between CRF and plasma metabolite patterns in 252 healthy adults from the cross-sectional Karlsruhe Metabolomics and Nutrition (KarMeN) study. CRF was determined by measuring the peak oxygen uptake during incremental exercise. Fasting plasma samples were analyzed by nuclear magnetic resonance spectroscopy and mass spectrometry coupled to one- or two-dimensional gas chromatography or liquid chromatography. Based on this multi-platform metabolomics approach, 427 plasma analytes were detected. Bi- and multivariate association analyses, adjusted for age and menopausal status, showed that CRF was linked to specific sets of metabolites primarily indicative of lipid metabolism. However, CRF-related metabolite patterns largely differed between sexes. While several phosphatidylcholines were linked to CRF in females, single lyso-phosphatidylcholines and sphingomyelins were associated with CRF in males. When controlling for further assessed clinical and phenotypical parameters, sex-specific CRF tended to be correlated with a smaller number of metabolites linked to lipid, amino acid, or xenobiotics-related metabolism. Interestingly, sex-specific CRF explanation models could be improved when including selected plasma analytes in addition to clinical and phenotypical variables. In summary, this study revealed sex-related differences in CRF-associated plasma metabolite patterns and proved known associations between CRF and risk factors for cardiometabolic diseases such as fat mass, visceral adipose tissue mass, or blood triglycerides in metabolically healthy individuals. Our findings indicate that covariates like sex and, especially, body composition have to be considered when studying blood metabolic markers related to CRF.

Cardiopulmonary fitness but not muscular fitness associated with visceral adipose tissue mass

PURPOSE

The purpose of this study is to identify the association between physical fitness (cardiopulmonary and musculoskeletal) and the distribution of abdominal fat in overweight and obese adults.

METHODS

Of the total 102 overweight and obese participants, 99 participants completed all measurements. Cardiopulmonary fitness was assessed by maximal oxygen consumption test and muscular fitness was assessed using 10 repetition max. Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were assessed by computed tomography (CT) at the level of lumbar spine 4-5.

RESULTS

Cardiopulmonary fitness was inversely associated with both VAT and SAT, while muscular fitness only inversely associated with SAT. Multiple linear regression analyses indicated that gender, age, and cardiopulmonary fitness, but not muscular fitness, were associated with VAT, and age, cardiopulmonary fitness, and muscular fitness were significantly associated with SAT.

CONCLUSIONS

Cardiopulmonary fitness is more closely related to both VAT and SAT while muscular fitness is related with SAT.

The Effect of Exercise Training on Total Daily Energy Expenditure and Body Composition in Weight-Stable Adults: A Randomized, Controlled Trial

BACKGROUND

The present study examined, among weight-stable overweight or obese adults, the effect of increasing doses of exercise energy expenditure (EEex) on changes in total daily energy expenditure (TDEE), total body energy stores, and body composition.

METHODS

Healthy, sedentary overweight/obese young adults were randomized to one of 3 groups for a period of 26 weeks: moderate-exercise (EEex goal of 17.5 kcal/kg/wk), high-exercise (EEex goal of 35 kcal/kg/wk), or observation group. Individuals maintained body weight within 3% of baseline. Pre/postphysical activity between-group measurements included body composition, calculated energy intake, TDEE, energy stores, and resting metabolic rate.

RESULTS

Sixty weight-stable individuals completed the protocols. Exercise groups increased EEex in a stepwise manner compared with the observation group (P < .001). There was no group effect on changes in TDEE, energy intake, fat-free mass, or resting metabolic rate. Fat mass and energy stores decreased among the females in the high-exercise group (P = .007).

CONCLUSIONS

The increase in EEex did not result in an equivalent increase in TDEE. There was a sex difference in the relationship among energy balance components. These results suggest a weight-independent compensatory response to exercise training with potentially a sex-specific adjustment in body composition.

Metabolic flexibility is impaired in women who are pregnant and overweight/obese and related to insulin resistance and inflammation

CONTEXT

Maternal obesity is a significant public health concern that contributes to unfavorable outcomes such as inflammation and insulin resistance. Women with obesity may have impaired metabolic flexibility (i.e. an inability to adjust substrate metabolism according to fuel availability). Impaired metabolic flexibility during pregnancy may mediate poor pregnancy outcomes in women with obesity.

PURPOSE

The purposes of this study were to: 1) compare metabolic flexibility between overweight/obese and lean women; and 2) determine the relationships between metabolic flexibility, inflammation following a high-fat meal, and maternal metabolic health outcomes (i.e. gestational weight gain and insulin resistance).

PROCEDURES

This interventional physiology study assessed lipid oxidation rates via indirect calorimetry before and after consumption of a high-fat meal. The percent change in lipid metabolism was calculated to determine 'metabolic flexibility.' Maternal inflammatory profiles (CRP, IL-6, IL-8, IL-10, IL-12, TNF-α) and insulin resistance (HOMA-IR) were determined via plasma analyses.

MAIN FINDINGS

64 women who were pregnant (lean = 35, overweight/obese = 29) participated between 32 and 38 weeks gestation. Lean women had significantly higher metabolic flexibility compared to overweight/obese women (lean 48.0 ± 34.1% vs overweight/obese 29.3 ± 34.3%, p = .035). Even when controlling for pre-pregnancy BMI, there was a negative relationship between metabolic flexibility and percent change in CRP among the overweight/obese group (r = -0.526, p = .017). Metabolic flexibility (per kg fat free mass) was negatively correlated with postprandial HOMA-IR (2 h: r = -0.325, p = .016; 4 h: r = -0.319, p = .019).

CONCLUSIONS

Overweight and obese women who are pregnant are less 'metabolically flexible' than lean women, and this is related to postprandial inflammation and insulin resistance.

Associations of Aerobic Fitness and Maximal Muscular Strength With Metabolites in Young Men

IMPORTANCE

High physical fitness is associated with a reduction in risk of cardiovascular diseases and death, but the underlying mechanisms are insufficiently understood.

OBJECTIVE

To determine how aerobic fitness and muscular strength are associated with serum metabolome measures.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study included Finnish men receiving military refresher training from May 5, 2015, to November 28, 2015, representing partly overlapping groups of individuals with the lowest vs highest aerobic fitness and the lowest vs highest muscular strength. Data analyses were conducted from January 1, 2018, to May 31, 2019.

MAIN OUTCOMES AND MEASURES

The associations of aerobic fitness (determined with maximum oxygen consumption in milliliters per minute per kilogram, measured with maximal cycle ergometer test) and muscular strength (determined with a maximal strength test for lower extremities in kilograms) with 66 metabolome measures from fasting serum samples (nuclear magnetic resonance-based metabolomics) were analyzed.

RESULTS

Participants included 580 Finnish men (mean [SD] age, 26.1 [6.5] years). Including overlap between groups, there were 196 men in the lowest aerobic fitness group and 197 men in the highest aerobic fitness group as well as 196 men in the lowest muscular strength group and 197 men in the highest muscular strength group. Of 66 studied metabolome measures, 48 differed between high vs low aerobic fitness groups, including small very low-density lipoprotein (standardized median difference, -0.67; 95% CI, -0.83 to -0.49), large high-density lipoprotein (standardized median difference, 0.89; 95% CI, 0.69-1.15), total triglyceride levels (standardized median difference, -0.52; 95% CI, -0.65 to -0.34), isoleucine (standardized median difference, -0.37; 95% CI, -0.55 to -0.16), leucine (standardized median difference, -0.55; 95% CI, -0.72 to -0.34), phenylalanine (standardized median difference, -0.54; 95% CI, -0.71 to -0.32), glycerol (standardized median difference, -0.64; 95% CI, -0.81 to -0.48), and glycoprotein (standardized median difference, -0.78; 95% CI, -0.95 to -0.62) concentration, a high unsaturation degree of fatty acids (standardized median difference, 0.59; 95% CI, 0.42-0.81), and apolipoprotein B to apolipoprotein A1 ratio (standardized median difference, -0.88; 95% CI, -1.08 to -0.67). Adding aerobic fitness into the regression model after age, education, smoking, use of alcohol, and dietary factors accounted for more than an additional 5% of variation for 25 metabolome measures (R2 range, 5.01%-15.90% by measure). With these 2 criteria, maximal muscular strength was not associated with any metabolome measures. Aerobic fitness was associated with high large high-density lipoprotein particle concentration (R2, 14.97%; 95% CI, 10.65%-20.85%), low apolipoprotein B to apolipoprotein A1 ratio (R2, 14.49%; 95% CI, 10.58%-19.51%), and low glycoprotein concentration (R2, 15.90%; 95% CI, 11.22%-21.51%). Aerobic fitness was also associated with low very low-density lipoprotein, triglyceride, isoleucine, leucine, phenylalanine, glycerol, and glycoprotein concentrations and with a high unsaturation degree of fatty acids. Adjusting for recent physical activity influenced the results minimally. Adjusting for body fat percentage showed that some of the associations were mechanistically associated with body fat percentage.

CONCLUSIONS AND RELEVANCE

This study provides data on the association of high aerobic fitness with underlying oxidative lipid metabolism associated with a reduction in cardiometabolic risk. High maximal muscular strength is not similarly associated with these benefits.

Exercise and incidence of myocardial infarction, stroke, hypertension, type 2 diabetes and site-specific cancers: prospective cohort study of 257 854 adults in South Korea

OBJECTIVE

The objective of this study was to examine the longitudinal associations of exercise frequency with the incidence of myocardial infarction, stroke, hypertension, type 2 diabetes and 10 different cancer outcomes.

DESIGN

A prospective cohort study.

SETTING

Physical examination data linked with the entire South Korean population's health insurance system: from 2002 to 2015.

PARTICIPANTS

257 854 South Korean adults who provided up to 7 repeat measures of exercise (defined as exercises causing sweat) and confounders.

PRIMARY OUTCOME MEASURES

Each disease incidence was defined using both fatal and non-fatal health records (a median follow-up period of 13 years).

RESULTS

Compared with no exercise category, the middle categories of exercise frequency (3-4 or 5-6 times/week) showed the lowest risk of myocardial infarction (HR 0.79; 95% CI 0.70 to 0.90), stroke (HR 0.80; 95% CI 0.73 to 0.89), hypertension (HR 0.86; 95% CI 0.85 to 0.88), type 2 diabetes (HR 0.87; 95% CI 0.84 to 0.89), stomach (HR 0.87; 95% CI 0.79 to 0.96), lung (HR 0.80; 95% CI 0.71 to 0.91), liver (HR 0.85; 95% CI 0.75 to 0.98) and head and neck cancers (HR 0.76; 95% CI 0.63 to 0.93; for 1-2 times/week), exhibiting J-shaped associations. There was, in general, little evidence of effect modification by body mass index, smoking, alcohol consumption, family history of disease and sex in these associations.

CONCLUSIONS

Moderate levels of sweat-inducing exercise showed the lowest risk of myocardial infarction, stroke, hypertension, type 2 diabetes, stomach, lung, liver and head and neck cancers. Public health and lifestyle interventions should, therefore, promote moderate levels of sweat-causing exercise as a behavioural prevention strategy for non-communicable diseases in a wider population of East Asians.

Coexistence of Pre-sarcopenia and Metabolic Syndrome in Arab Men

OBJECTIVE

The present single-center observational study determined the prevalence and coexistence of sarcopenia, pre-sarcopenia, and metabolic syndrome (MetS) among apparently healthy Arab men and whether having both conditions present a unique cardiometabolic profile that is distinct than having the conditions separately.

METHODS

A total of 471 out of 530 Arab men aged 20-77 years old were included after screening for the presence of pre-sarcopenia (ALM/ht² < 7.26 kg/m²), sarcopenia (presence of both low muscle mass and low function), and MetS. MetS screening was done using the definition by the NCEP-ATP III. Based on the screening results, the participants were classified as control (normal) group (N = 328), MetS only (N = 73), pre-sarcopenia only (N = 64), and MetS + pre-sarcopenia (N = 6).

RESULTS

Pre-sarcopenia without MetS was observed in 64 participants (13.6%), while MetS without pre-sarcopenia was observed in 73 participants (15.5%). MetS + pre-sarcopenia was observed only in 6 participants (1.3%). None of the participants had sarcopenia. Age- and BMI-adjusted comparisons showed that those with MetS + pre-sarcopenia had the highest diastolic blood pressure and triglyceride levels as compared to all groups (p values < 0.001). MetS + pre-sarcopenia group also had the highest levels of glucose and the lowest lean arms-legs/BMI ratio than control and pre-sarcopenia groups (p values < 0.001 and 0.005, respectively).

CONCLUSION

The prevalence of pre-sarcopenia + MetS is low among young adult Arab men, but shows a unique cardiometabolic profile that is worse than those having only one of the conditions. Further investigations should be done among Arab women and the elderly.

Weight loss but not gains in cardiorespiratory fitness after exercise-training predicts improved health risk factors in metabolic syndrome

BACKGROUND AND AIMS

To examine the relationship between changes in cardiorespiratory fitness (CRF; estimated by VO₂max) and metabolic syndrome (MetS) after an exercise training intervention to confirm/contradict the high association found in cross-sectional observational studies.

METHODS AND RESULTS

MetS individuals (54 ± 8 yrs old; BMI of 32 ± 5) were randomly allocated (6:1 ratio) to a group that exercised trained for 16-weeks (EXER; n = 138) or a control sedentary group (CONT; n = 22). At baseline, MetS components, body composition and exercise responses were similar between groups (all P > 0.05). After 16 weeks of intervention, only EXER reduced body weight, waist circumference (-1.21 ± 0.22 kg and -2.7 ± 0.3 cm; P < 0.001), mean arterial blood pressure and hence the composite MetS Z-score (-7.06 ± 0.77 mmHg and -0.21 ± 0.03 SD; P < 0.001). In the EXER group, CRF increased by 16% (0.302 ± 0.026, 95% CI 0.346 to 0.259 LO₂·min^-1; P < 0.001) but was not a significant predictor of MetS Z-score improvements (r = -0.231; β = -0.024; P = 0.788). Instead, body weight reductions predicted 25% of MetS Z-score changes (r = 0.508; β = 0.360; P = 0.001).

CONCLUSIONS

In MetS individuals, the exercise-training increases in CRF are not predictive of the improvements in their health risk factors. Instead, body weight loss (<2%) was a significant contributor to the improved MetS Z-score and thus should be emphasized in exercise training programs. ClinicalTrials.gov identifier: NCT03019796.

Predictive Modeling of VO2max Based on 20 m Shuttle Run Test for Young Healthy People

This study presents mathematical models for predicting VO2max based on a 20 m shuttle run and anthropometric parameters. The research was conducted with data provided by 308 young healthy people (aged 20.6 ± 1.6). The research group includes 154 females (aged 20.3 ± 1.2) and 154 males (aged 20.8 ± 1.8). Twenty-four variables were used to build the models, including one dependent variable and 23 independent variables. The predictive methods of analysis include: the classical model of ordinary least squares (OLS) regression, regularized methods such as ridge regression and Lasso regression, artificial neural networks such as the multilayer perceptron (MLP) and radial basis function (RBF) network. All models were calculated in R software (version 3.5.0, R Foundation for Statistical Computing, Vienna, Austria). The study also involved variable selection methods (Lasso and stepwise regressions) to identify optimum predictors for the analysed study group. In order to compare and choose the best model, leave-one-out cross-validation (LOOCV) was used. The paper presents three types of models: for females, males and the whole group. An analysis has revealed that the models for females ( RMSE C V = 4.07 mL·kg−1·min−1) are characterised by a smaller degree of error as compared to male models ( RMSE C V = 5.30 mL·kg−1·min−1). The model accounting for sex generated an error level of RMSE C V = 4.78 mL·kg−1·min−1.

Training intensity relative to ventilatory thresholds determines cardiorespiratory fitness improvements in sedentary adults with obesity

The aim of the present study was to study if training intensity relative to ventilatory thresholds (VTs) determines the improvements in cardiorespiratory fitness (CRF) in middle-aged sedentary individuals with obesity. Before and after 16-weeks of HIIT (43-min alternating bouts at 70/90% of HR_MAX), oxygen consumption ( V˙ O₂) and heart rate (HR) at ventilatory threshold 1 ( V˙ O_2VT1, HR_VT1), ventilatory threshold 2 ( V˙ O_2VT2, HR_VT2) and at maximal effort ( V˙ O_2MAX, HR_MAX) were assessed during a graded cycle-ergometer exercise test. Retrospectively, participants were divided into two groups based on whether training intensities were under (UNDER; n = 39) or over (OVER; n = 37) VT₁ and VT₂. At baseline, age, body composition, V˙ O_2VT1, V˙ O_2VT2, and HR_MAX were similar in both groups. However, V˙ O_2MAX was higher in OVER (P = 0.033), whereas HR_VT1 and HR_VT2 were higher in UNDER (P < 0.05). V˙ O_2MAX (9.0%) and HR_MAX (2.2%) improved similarly in both groups. V˙ O_2VT1 and V˙ O_2VT2 improved with training in both groups (P < 0.001) but the improvement was larger in OVER versus UNDER in V˙ O_2VT1 (P = 0.013) and tended to be higher in V˙ O_2VT2 (P = 0.068). HR_VT1 increased only in OVER (P < 0.001), whereas HR_VT2 did not change in any group (P = 0.248). A 16-week programme of HIIT improves V˙ O_2MAX similarly in individuals training at intensities over or under their VTs. However, individuals training over their VTs showed a larger improvements in V˙ O_2VT1 expanding exercise workloads fuelled by oxidative metabolism.

Central and peripheral effects of physical exercise without weight reduction in obese and lean mice

To investigate the central (hypothalamic) and peripheral effects of exercise without body weight change in diet-induced obesity (DIO). Twelve-week-old male C57Bl/6 mice received a control (C) or a high-fat diet (H). Half of them had free access to running wheels for 5 days/week for 10 weeks (CE) and HE, respectively). Hypothalamic expression of genes related to energy homeostasis, and leptin (Stat3 and p-Stat3) and insulin (Akt and p-Akt) signaling were evaluated. Glucose and leptin tolerance, peripheral insulin sensitivity, and plasma insulin, leptin and adiponectin were determined. Perigonadal and retroperitoneal fat depots were increased by diet but reduced by exercise despite lack of effect of exercise on body weight. Blood glucose during intraperitoneal glucose tolerance test (ipGTT) was higher and glucose decay during intraperitoneal insulin tolerance test (ipITT) was lower in H and HE compared with C and CE. Exercise increased liver p-Akt expression and reduced fast glycemia. High-fat diet increased plasma insulin and leptin. Exercise had no effect on insulin but decreased leptin and increased adiponectin. Leptin inhibited food intake in all groups. Hypothalamic total and p-Stat3 and Akt were similar amongst the groups despite higher plasma levels of leptin and insulin in H and HE mice. High-fat diet modulated gene expression favoring a positive energy balance. Exercise only marginally changed the gene expression. Exercise induced positive changes (decreased fast glycemia and fat depots; increased liver insulin signaling and adiponectin concentration) without weight loss. Thus, despite reducing body weight could bring additional benefits, the effects of exercise must not be overlooked when weight reduction is not achieved.

Association between cardiorespiratory fitness and metabolic risk factors in a population with mild to severe obesity

Background

Previous literature suggests the beneficial effects of fitness on abdominal obesity may be attenuated in obesity and abolished in severe obesity. It is unclear whether the beneficial association between fitness and health is similarly present in those with mild and severe obesity.

Methods

Patients from the Wharton Medical Clinic (n = 853) completed a clinical examination and maximal treadmill test. Patients were categorized into fit and unfit based on age- and sex-categories and body mass index (BMI) class (mild: ≤ 34.9 kg/m², moderate: 35–39.9 kg/m² or severe obesity: ≥ 40 kg/m²).

Results

Within the sample, 41% of participants with mild obesity had high fitness whereas only 25% and 11% of the participants with moderate and severe obesity, respectively, had high fitness. BMI category was independently associated with most of the metabolic risk factors, while fitness was only independently associated with systolic blood pressure and triglycerides (P < 0.05). The prevalent relative risk for pre-clinical hypertension, hypertriglyceridemia and hypoalphalipoproteinemia and pre-diabetes was only elevated in the unfit moderate and severe obesity groups (P < 0.05), and fitness groups were only significantly different in their relative risk for prevalent pre-clinical hypertension within the severe obesity group (p = 0.03). High fitness was associated with smaller waist circumferences, with differences between high and low fitness being larger in those with severe obesity than mild obesity (Men: P = 0.06, Women: P = 0.0005).

Conclusions

Thus, in contrast to previous observations, the favourable associations of having high fitness and health may be similar if not augmented in individuals with severe compared to mild obesity.

Physical activity and diet on atherogenic index of plasma among adults in the United States: mediation considerations by central adiposity

BACKGROUND/OBJECTIVES

The potential interactive or combined association of moderate-to-vigorous physical activity (MVPA) and dietary behavior with atherogenic index of plasma (AIP) has yet to be explored in a representative sample of US adults. Thus, the study aim was to examine the association of MVPA and dietary behavior on AIP, with potential mediation considerations by central adiposity.

SUBJECTS/METHODS

Data from the National Health and Nutrition Examination Survey were used (N = 2701 adults aged 20-85 years). AIP was evaluated via blood sample, MVPA was assessed via accelerometry, and two 24-h recalls were utilized to calculate Healthy Eating Index (HEI), a metric of dietary quality. Android-specific dual energy X-ray absorptiometry (DXA) was used to measure central adiposity.

RESULTS

Meeting MVPA guidelines (OR = 0.58; 95% CI: 0.41-0.82; P = 0.004), but not meeting dietary guidelines (OR = 0.89; 95% CI: 0.69-1.15; P = 0.37), was associated with reduced odds of having an elevated (>0.24 mmol/L) AIP. Having one (OR = 0.68; 95% CI: 0.52-0.89; P = 0.007) or both (OR = 0.55; 95_% CI: 0.37-0.82; P = 0.005) health-enhancing behaviors (adequate physical activity and/or healthy diet), when compared to having neither, was associated with reduced odds (32 and 45%) for having an elevated AIP. The relative excess risk due to interaction (RERI) was 0.06 (95% CI: -0.06 to 0.18; P = 0.31), suggesting there is no additive interaction between MVPA and dietary behavior on AIP. All associations were attenuated when including central adiposity as a covariate, suggesting a mediation effect of central adiposity.

CONCLUSIONS

MVPA is independently associated with reduced odds of having an elevated AIP, having both adequate levels of MVPA and a healthy diet does not substantively reduce the odds of AIP, and there is no additive interaction effect between MVPA and diet on AIP. Central adiposity mediated the relationship between MVPA and AIP.

Cardiorespiratory fitness, fatness and incident diabetes

AIMS

Increases in prevalence have led to a diabetes pandemic. Obesity and low cardiorespiratory fitness (CRF) are considered to be central mechanisms. We investigated if the effect of CRF on diabetes risk was equivalent across levels of fatness among healthy men.

METHODS

In total 4988 middle-aged Caucasian employed men free of cardiovascular disease, diabetes and cancer were included from the Copenhagen Male Study starting in 1970-71. CRF was assessed using a sub-maximal bicycle ergometer test and body mass index (BMI) was measured by height and weight. Their interaction and stratified associations with diabetes incidence were estimated in multivariable Cox-models including conventional risk factors and social class. Diabetes incidence was assessed through a national register.

RESULTS

During 44 years of follow-up, 518 (10.4%) incident cases of diabetes occurred. In the multi-adjusted model, the obese had a significantly higher risk of diabetes compared to normal weight men (Hazard Ratio (HR):4.89; 95% CI: 3.62-6.61) and CRF was significantly inversely associated with diabetes (HR:0.86; 95% CI: 0.75-0.98 per 10-unit increase in ml/kg/min¹ CRF). A significant multi-adjusted interaction between CRF, BMI and diabetes was found (p=0.009). The stratified multi-adjusted analyses on BMI showed a significantly stronger reduced risk of diabetes per 10-unit increase in ml/kg/min¹ of CRF among the obese (HR:0.58; CI: 0.38-0.89), but a weaker association among overweight (HR:0.86; CI: 0.71-1.03) and normal weight (HR:0.97; CI: 0.76-1.23).

CONCLUSION

High CRF has a stronger protective effect on diabetes among obese than among normal weight men, supporting the recommendation of fitness-enhancing physical activity for preventing diabetes among the obese.

Aerobic exercise elevates markers of angiogenesis and macrophage IL-6 gene expression in the subcutaneous adipose tissue of overweight-to-obese adults

Alterations in the inflammatory state, metabolic function, and structure of subcutaneous adipose tissue (SAT) can impact the development of insulin resistance in obesity. Exercise can improve metabolic health in obesity, but the effects of exercise on SAT are not well known. The purpose of this study was to examine the effects of acute exercise and habitual exercise training on mRNA expression of markers of lipid metabolism, inflammation, fibrosis, and hypoxia/angiogenesis in SAT, as well as adipocyte cell size. We recruited overweight-to-obese adults who exercised regularly (ACTIVE: n = 8) or were sedentary (SED: n = 12). The groups were well matched for age (27 ± 1 vs. 24 ± 2 yr), body mass index (29 ± 1 vs. 27 ± 1 kg/m²), and body composition (30 ± 1 vs. 29 ± 1% body fat), but as expected, cardiorespiratory fitness was greater in ACTIVE vs. SED (V̇o_2peak: 51 ± 3 vs. 42 ± 1 ml·kg fat-free mass^-1·min^-1; P = 0.01). Abdominal SAT biopsy samples were obtained before and 1 h after a single session of aerobic exercise (60 min at ~65% V̇o_2peak). The exercise session increased SAT mRNA expression of VEGFA, an important regulator of angiogenic processes, in both groups. In addition, SAT from ACTIVE subjects had greater mRNA expression of the endothelial cell marker CD31 compared with SED, which may be a cumulative effect of the transient increases in VEGFA with regular exercise. We also magnetically sorted CD14+ immune cells from SAT samples and found that IL-6 expression was elevated in ACTIVE compared with SED. In conclusion, exercise initiates increases in factors related to angiogenic processes and may promote alterations in macrophage inflammation in SAT.NEW & NOTEWORTHY Acute exercise in overweight/obese adults increased subcutaneous adipose tissue (SAT) mRNA expression of VEGFA, an important regulator of angiogenesis and capillary growth. In addition, subjects that regularly exercise had elevated SAT CD31 mRNA expression and elevated IL-6 mRNA in adipose tissue macrophages compared with nonexercisers. This study demonstrates that aerobic exercise may alter processes related to whole body metabolic outcomes in obesity, such as angiogenesis and immune response, in the SAT of overweight/obese adults.

Body-Brain Connections: The Effects of Obesity and Behavioral Interventions on Neurocognitive Aging

Obesity is a growing public health problem in the United States, particularly in middle-aged and older adults. Although the key factors leading to a population increase in body weight are still under investigation, there is evidence that certain behavioral interventions can mitigate the negative cognitive and brain ("neurocognitive") health consequences of obesity. The two primary behaviors most often targeted for weight loss are caloric intake and physical activity. These behaviors might have independent, as well as overlapping/synergistic effects on neurocognitive health. To date obesity is often described independently from behavioral interventions in regards to neurocognitive outcomes, yet there is conceptual and mechanistic overlap between these constructs. This review summarizes evidence linking obesity and modifiable behaviors, such as physical activity and diet, with brain morphology (e.g., gray and white matter volume and integrity), brain function (e.g., functional activation and connectivity), and cognitive function across the adult lifespan. In particular, we review evidence bearing on the following question: Are associations between obesity and brain health in aging adults modifiable by behavioral interventions?

Cardiorespiratory Fitness and Adiposity as Determinants of Metabolic Health-Pooled Analysis of Two Twin Cohorts

CONTEXT

The joint effects of cardiorespiratory fitness (CRF) and body composition on metabolic health are not well known.

OBJECTIVE

To examine the associations of CRF, fat-free mass index (FFMI), and fat mass index (FMI) with metabolic health in individual twins and controlling for genetic and shared environmental effects by studying monozygotic intrapair differences.

DESIGN, SETTING, AND PARTICIPANTS

Two cross-sectional samples of healthy adult monozygotic and dizygotic twins were drawn from population-based Danish and Finnish national twin registries (n = 996 and n = 309).

MAIN MEASURES

CRF was defined as VO2max divided by fat-free mass. Insulin sensitivity and acute insulin response indices were derived from an oral glucose tolerance test. A continuous metabolic syndrome score was calculated. Visceral and liver fat were measured in the Finnish sample. Associations were analyzed separately in both cohorts with multivariate linear regression and aggregated with meta-analytic methods.

RESULTS

Insulin sensitivity, acute insulin response, metabolic syndrome score, visceral, and liver fat amount had strong and statistically significant associations with FMI (|β| 0.53 to 0.79), whereas their associations with CRF and FFMI were at most weak (|β| 0.02 to 0.15). The results of the monozygotic intrapair differences analysis showed the same pattern.

CONCLUSIONS

Although FMI is strongly associated with worsening of metabolic health traits, even after controlling for genetic and shared environmental factors, there was little evidence for the effects of CRF or FFMI on metabolic health. This suggests that changing FMI rather than CRF or FFMI may affect metabolic health irrespective of genetic or early environmental determinants.

Outcomes of a community-based lifestyle programme for adults with diabetes or pre-diabetes

INTRODUCTION Diabetes, a long-term condition increasing in prevalence, requires ongoing healthcare management. Exercise alongside lifestyle education and support is effective for diabetes management. AIM To investigate clinical outcomes and acceptability of a community-based lifestyle programme for adults with diabetes/prediabetes at programme completion and 3-month follow-up. METHODS The 12-week community programme included twice-weekly sessions of self-management education and exercise, supervised by a physiotherapist, physiotherapy students and a nurse. Clinical outcomes assessed were cardiorespiratory fitness, waist circumference, exercise behaviour and self-efficacy. A standardised evaluation form was used to assess programme acceptability. RESULTS Clinically significant improvements were found from baseline (n = 36) to programme completion (n = 25) and 3-months follow-up (n = 20) for the six minute walk test (87 m (95%CI 65-109; p ≤ 0.01), 60 m (95%CI 21-100; p ≤ 0.01)), waist circumference (-3 cm (95%CI -6 to -1), -3 cm (95%CI -6 to 1)), exercise behaviour (aerobic exercise 53 min/week (95%CI 26 to 81; p ≤ 0.01), 71 min/week (95%CI 25 to 118; p ≤ 0.01)) and self-efficacy (0.7 (95%CI -0.2 to 1.6), 0.8 (95%CI 0.04 to 1.5)). Good programme acceptability was demonstrated by themes suggesting a culturally supportive, motivating, friendly, informative atmosphere within the programme. The attrition rate was 30% but there were no adverse medical events related to the programme. DISCUSSION The programme was safe and culturally acceptable and outcomes demonstrated clinical benefit to participants. The attrition rate was largely due to medical reasons unrelated to the programme. This model of a community-based lifestyle programme has the potential to be reproduced in other regions and in adults with similar long-term conditions. KEYWORDS Diabetes Mellitus Type II; Prediabetic state; Co-morbidity; Exercise; Self-management.

High-intensity interval training improves obstructive sleep apnoea

Background

Three hours per week of vigorous physical activity is found to be associated with reduced odds of sleep-disordered breathing.

Aim

To investigate whether 12 weeks of high-intensity interval training (HIIT) reduced the apnoea–hypopnea index (AHI) in obese subjects with moderate-to-severe obstructive sleep apnoea.

Methods

In a prospective randomised controlled exercise study, 30 (body mass index 37±6 kg/m², age 51±9 years) patients with sleep apnoea (AHI 41.5±25.3 events/hour) were randomised 1:1 to control or 12 weeks of supervised HIIT (4×4 min of treadmill running or walking at 90%–95% of maximal heart rate two times per week).

Results

In the HIIT group, the AHI was reduced by 7.5±11.6 events/hour (within-group p<0.05), self-reported sleepiness (Epworth scale) improved from 10.0±3.6 to 7.3±3.7 (between-group p<0.05) and maximal oxygen uptake improved from 28.2±7.4 to 30.2±7.7 mL/kg/min (between-group p<0.05) from baseline to 12 weeks. The AHI, self-reported sleepiness and VO_2maxwere unchanged from baseline to 12 weeks in controls (baseline AHI 50.3±25.5 events/hour, Epworth score 5.9±4.3, maximal oxygen uptake 27.0±6.8 mL/kg/min). Body weight remained unchanged in both groups.

Conclusion

Twelve weeks of HIIT improved the AHI and self-reported daytime sleepiness in subjects with obese sleep apnoea without any change in the desaturation index and body weight.

Determinants of High Fasting Insulin and Insulin Resistance Among Overweight/Obese Adolescents

Hyperinsulinaemia is the earliest subclinical metabolic abnormality, which precedes insulin resistance in obese children. An investigation was conducted on the potential predictors of fasting insulin and insulin resistance among overweight/obese adolescents in a developing Asian country. A total of 173 overweight/obese (BMI > 85^th percentile) multi-ethnic Malaysian adolescents aged 13 were recruited from 23 randomly selected schools in this cross-sectional study. Waist circumference (WC), body fat percentage (BF%), physical fitness score (PFS), fasting glucose and fasting insulin were measured. Insulin resistance was calculated using homeostasis model assessment of insulin resistance (HOMA-IR). Adjusted stepwise multiple regression analysis was performed to predict fasting insulin and HOMA-IR. Covariates included pubertal stage, socioeconomic status, nutritional and physical activity scores. One-third of our adolescents were insulin resistant, with girls having significantly higher fasting insulin and HOMA-IR than boys. Gender, pubertal stage, BMI, WC and BF% had significant, positive moderate correlations with fasting insulin and HOMA-IR while PFS was inversely correlated (p < 0.05). Fasting insulin was primarily predicted by gender-girls (Beta = 0.305, p < 0.0001), higher BMI (Beta = −0.254, p = 0.02) and greater WC (Beta = 0.242, p = 0.03). This study demonstrated that gender, BMI and WC are simple predictors of fasting insulin and insulin resistance in overweight/obese adolescents.

Influence of cardiorespiratory fitness and physical activity levels on cardiometabolic risk factors during menopause transition: A MONET study

To determine the influence of cardiorespiratory fitness (hereafter “fitness”) and physical activity levels on cardiometabolic risk factors in premenopausal women going through the menopause transition. An ancillary study including 66 premenopausal women who participated to a 5-year observational, longitudinal study (2004 to 2009 in Ottawa) on the effects of menopause transition on body composition and cardiometabolic risk factors. Women underwent a graded exercise test on treadmill to measure peak oxygen uptake (VO₂ peak) at year 1 and 5 and physical activity levels were measured using accelerometers. Cardiometabolic risk factors included: waist circumference, fasting plasma lipids, glucose and insulin levels, HOMA-IR score, c-reactive protein, apolipoprotein B (apoB) and resting systolic and diastolic blood pressure. Change in fitness was not associated with changes in cardiometabolic risk factors. The changes in total physical activity levels on the other hand showed a significant negative association with apoB levels. Three-way linear mixed model repeated measures, showed lower values of waist circumference, fasting triglycerides, insulin levels, HOMA-IR score, apoB and diastolic blood pressure in women with a fitness ≥ 30.0 mlO₂ kg^− 1 min^− 1 compared to women with a fitness < 30.0 mlO₂ kg^− 1 min^− 1 (P < 0.05). However, only fasting triglycerides was lower in women with physical activity levels ≥ 770.0 Kcal/day (P < 0.05). Between fitness and physical activity levels, fitness was associated with more favorable values of cardiometabolic risk factors in women followed for 5 years during the menopause transition.

•

Fitness and physical activity levels are independent predictors of CVD.

•

Change in total physical activity levels was negatively association with apoB.

•

Fitness was associated with more favorable values of cardiometabolic risk factors.

Addition of Cardiorespiratory Fitness Within an Obesity Risk Classification Model Identifies Men at Increased Risk of All-Cause Mortality

OBJECTIVE

Guidelines for identification of obesity-related risk which stratify disease risk using specific combinations of body mass index and waist circumference. Whether the addition of cardiorespiratory fitness, an independent predictor of disease risk, provides better risk prediction of all-cause mortality within current body mass index and waist circumference categories is unknown. The study objective was to determine whether the addition of cardiorespiratory fitness improves prediction of all-cause mortality risk classified by the combination of body mass index and waist circumference.

METHODS

We performed a prospective observational study using data from the Aerobics Center Longitudinal Study. A total of 31,267 men (mean age, 43.9 years; standard deviation, 9.4 years) who completed a baseline medical examination between 1974 and 2002 were included. The main outcome measure was all-cause mortality. Participants were grouped using body mass index- and waist circumference-specific threshold combinations: normal body mass index: 18.5 to 24.9 kg/m(2), waist circumference threshold of 90 cm; overweight body mass index: 25.0 to 29.9 kg/m(2), waist circumference threshold of 100 cm, and obese body mass index: 30.0 to 34.9 kg/m(2), waist circumference threshold of 110 cm. Participants were classified using cardiorespiratory fitness as unfit or fit, where unfit was the lowest fifth of the age-specified distribution of maximal exercise test time on the treadmill among the entire Aerobics Center Longitudinal Study population.

RESULTS

A total of 1399 deaths occurred over a follow-up of 14.1 ± 7.4 years, for a total of 439,991 person-years of observation. Men who were unfit and had normal body mass index with waist circumference <90 cm and ≥90 cm had 95% (hazard ratio [HR], 1.95; 95% confidence interval [CI], 1.34-2.83) and 163% (HR, 2.63; 95% CI, 1.58-4.40) higher mortality risk than men who were fit, respectively (P <.05). Men who were unfit and overweight had 41% (HR, 1.41; 95% CI, 1.04-1.90) higher mortality risk with a waist circumference <100 cm (P <.05), but were at no greater risk (HR, 1.30; 95% CI, 0.92-1.84) if their waist circumference was ≥100 cm (P = .14). Men who were unfit and obese were not at increased mortality risk (HR, 1.37; 95% CI, 0.90-2.09) with a waist circumference <110 cm (P = .14), but were at 111% (HR, 2.11; 95% CI, 1.31-3.42) increased risk with a waist circumference ≥110 cm (P <.05).

CONCLUSIONS

For most of the body mass index and waist circumference categories, inclusion of cardiorespiratory fitness allowed for improved identification of men at increased mortality risk.

Childhood fitness reduces the long-term cardiometabolic risks associated with childhood obesity

OBJECTIVE

The objective of this study was to examine whether childhood cardiorespiratory fitness attenuates or modifies the long-term cardiometabolic risks associated with childhood obesity.

DESIGN AND METHODS

The study consisted of a 20-year follow-up of 1792 adults who participated in the 1985 Australian Schools Health and Fitness Survey when they were 7-15 years of age. Baseline measures included a 1.6-km run to assess cardiorespiratory fitness and waist circumference to assess abdominal adiposity. At follow-up, participants attended study clinics where indicators of Metabolic Syndrome (MetS) (waist circumference, blood pressure, fasting blood glucose and lipids) were measured and cardiorespiratory fitness was reassessed using a submaximal graded exercise test.

RESULTS

Both high waist circumference and low cardiorespiratory fitness in childhood were significant independent predictors of MetS in early adulthood. The mutually adjusted relative risk of adult MetS was 3.00 (95% confidence interval: 1.85-4.89) for children in the highest (vs lowest) third of waist circumference and 0.64 (95% confidence interval: 0.43-0.96) for children with high (vs low) cardiorespiratory fitness. No significant interaction between waist circumference and fitness was observed, with higher levels of childhood fitness associated with lower risks of adult MetS among those with either low or high childhood waist circumference values. Participants who had both high waist circumference and low cardiorespiratory fitness in childhood were 8.5 times more likely to have MetS in adulthood than those who had low waist circumference and high cardiorespiratory fitness in childhood. Regardless of childhood obesity status, participants with low childhood fitness who increased their relative fitness by adulthood had a substantially lower prevalence of MetS than those who remained low fit.

CONCLUSIONS

Childhood waist circumference and cardiorespiratory fitness are both strongly associated with cardiometabolic health in later life. Higher levels of cardiorespiratory fitness substantially reduce the risk of adult MetS, even among those with abdominal obesity in childhood.

Effects of exercise intensity and nutrition advice on myocardial function in obese children and adolescents: a multicentre randomised controlled trial study protocol

INTRODUCTION

The prevalence of paediatric obesity is increasing, and with it, lifestyle-related diseases in children and adolescents. High-intensity interval training (HIIT) has recently been explored as an alternate to traditional moderate-intensity continuous training (MICT) in adults with chronic disease and has been shown to induce a rapid reversal of subclinical disease markers in obese children and adolescents. The primary aim of this study is to compare the effects of HIIT with MICT on myocardial function in obese children and adolescents.

METHODS AND ANALYSIS

Multicentre randomised controlled trial of 100 obese children and adolescents in the cities of Trondheim (Norway) and Brisbane (Australia). The trial will examine the efficacy of HIIT to improve cardiometabolic outcomes in obese children and adolescents. Participants will be randomised to (1) HIIT and nutrition advice, (2) MICT and nutrition advice or (3) nutrition advice. Participants will partake in supervised exercise training and/or nutrition sessions for 3 months. Measurements for study end points will occur at baseline, 3 months (postintervention) and 12 months (follow-up). The primary end point is myocardial function (peak systolic tissue velocity). Secondary end points include vascular function (flow-mediated dilation assessment), quantity of visceral and subcutaneous adipose tissue, myocardial structure and function, body composition, cardiorespiratory fitness, autonomic function, blood biochemistry, physical activity and nutrition. Lean, healthy children and adolescents will complete measurements for all study end points at one time point for comparative cross-sectional analyses.

ETHICS AND DISSEMINATION

This randomised controlled trial will generate substantial information regarding the effects of exercise intensity on paediatric obesity, specifically the cardiometabolic health of this at-risk population. It is expected that communication of results will allow for the development of more effective evidence-based exercise prescription guidelines in this population while investigating the benefits of HIIT on subclinical markers of disease.

TRIAL REGISTRATION NUMBER

NCT01991106.

Low Cardiorespiratory Fitness Is Associated with Markers of Insulin Resistance in Young, Normal Weight, Hispanic Women

BACKGROUND

Low cardiorespiratory fitness (CRF) and its decline over time are predictors of the development of diabetes in black and Caucasian women, independent of obesity. It is unclear, however, if the adverse effect of low CRF on the risk of diabetes in Hispanic women is mediated by obesity. Our purpose was to determine the associations of CRF with markers of insulin resistance in 68 normal weight Hispanic women.

METHODS

Obesity indicators included body mass index (BMI), body composition by DXA, and waist circumference. CRF was measured by indirect calorimetry. A glucose tolerance test was used to measure markers of insulin resistance: homeostasis model assessment, fasting insulin, 2-hr insulin, area under the curve insulin, qualitative insulin sensitivity check, and insulin sensitivity index. Pearson correlation and multiple regression analyses were used to identify associations between CRF and markers of insulin resistance. Multivariate ANOVA was used to compare markers of insulin resistance over quartiles of CRF.

RESULTS

Low CRF was significantly associated with all markers of insulin resistance (P < 0.01). These associations were independent of age, BMI, waist circumference, family history of T2DM, and triglycerides (CRF standardized beta range: -0.27 to -0.46, P < 0.05). However, these associations were attenuated when body composition, specifically fat-free mass, was entered into the model (CRF standardized beta range: -0.03 to 0.21, P > 0.05). All markers of insulin resistance improved linearly across CRF quartiles (P < 0.05).

CONCLUSIONS

Our findings suggest that low CRF may be an important predictor of diabetes risk in Hispanic women and that fat-free mass rather than overall body adiposity mediates these relationships.

Body Mass Index and Kidney Stones: A Cohort Study of Japanese Men

Background

In Japan, the incidence of kidney stones has increased markedly in recent decades. Major causes of kidney stones remain unclear, and limited data are available on the relationship between overweight/obesity and the incidence of kidney stones. We therefore evaluated body mass index (BMI) and the incidence of kidney stones in Japanese men.

Methods

Of the workers at a gas company, 5984 males aged 20–40 years underwent a medical examination in 1985 (baseline). This study includes 4074 of the men, who were free of kidney stones at baseline and underwent a second medical examination performed between April 2004 and March 2005. BMI was calculated from measured height and weight in 1985, and men were categorized into tertiles. The development of kidney stones during follow-up was based on self-reports from questionnaires at the second medical examination.

Results

The average duration of follow-up was 19 years, with 258 participants developing kidney stones during this period. Using the lowest BMI (1st tertile) group as a reference, the hazard ratios (95% confidence intervals [CIs]) for the 2nd and 3rd BMI tertiles were: 1.26 (95% CI, 0.92–1.73) and 1.44 (95% CI, 1.06–1.96), respectively (P for trend = 0.019). After additionally adjusting for potential confounders, such as age, systolic blood pressure, cardiorespiratory fitness, cigarette smoking, and alcohol consumption, the hazard ratios were 1.28 (95% CI, 0.93–1.76) and 1.41 (95% CI, 1.02–1.97), respectively (P for trend = 0.041).

Conclusions

These results suggest that increased BMI is a risk factor for kidney stones in Japanese men.

V. The differential association of adiposity and fitness with cognitive control in preadolescent children

With the increasing prevalence of sedentary behaviors during childhood, a greater understanding of the extent to which excess adiposity and aerobic fitness relate to cognitive health is of increasing importance. To date, however, the vast majority of research in this area has focused on adiposity or fitness, rather than the possible inter-relationship, as it relates to cognition. Accordingly, this study examined the differential associations between body composition, aerobic fitness, and cognitive control in a sample of 204 (96 female) preadolescent children. Participants completed a modified flanker task (i.e., inhibition) and a switch task (i.e., cognitive flexibility) to assess two aspects of cognitive control. Findings from this study indicate that fitness and adiposity appear to be separable factors as they relate to cognitive control, given that the interaction of fitness and adiposity was observed to be nonsignificant for both the flanker and switch tasks. Fitness exhibited an independent association with both inhibition and cognitive flexibility whereas adiposity exhibited an independent association only with cognitive flexibility. These results suggest that while childhood obesity and fitness appear to both be related to cognitive control, they may be differentially associated with its component processes.

Physical activity, body composition and metabolic syndrome in young adults

OBJECTIVE

Low physical activity (PA) is a major risk factor for cardiovascular and metabolic disorders in all age groups. We measured intensity and volume of PA and examined the associations between PA and the metabolic syndrome (MS), its components and body composition among young Finnish adults.

RESEARCH DESIGN AND METHODS

The study comprises 991 men and women born 1985-86, who participated in a clinical study during the years 2009-11 which included assessments of metabolism, body composition and PA. Objectively measured (SenseWear Armband) five-day PA data was available from 737 participants and was expressed in metabolic equivalents of task (MET).

RESULTS

The prevalence of MS ranged between 8-10%. Higher total mean volume (MET-hours) or intensity (MET) were negatively associated with the risk of MS and separate components of MS, while the time spent at sedentary level of PA was positively associated with MS.

CONCLUSIONS

MS was prevalent in approximately every tenth of the young adults at the age of 24 years. Higher total mean intensity and volume rates as well as longer duration spent at moderate and vigorous PA level had a beneficial impact on the risk of MS. Longer time spent at the sedentary level of PA increased the risk of MS.

Insulin secretion response during oral glucose tolerance test is related to low cardiorespiratory fitness in obese adolescents

BACKGROUND

The obesity paradox refers to a category of subjects who may be less prone to develop co-morbidities, such as type 2 diabetes. Cardiorespiratory fitness (CRF) has been identified as one of the key factors. We aimed at exploring the difference in insulin metabolism between fit and unfit obese adolescents.

METHODS

We recruited 22 obese adolescents and assessed CRF during an incremental treadmill test. According to a cut-off at 80% of predicted maximal oxygen consumption (VO2max), subjects were separated into low or normal CRF. Body composition was determined by densitometry. Serum levels of insulin were measured sequentially during an oral glucose tolerance test and insulin secretion responses were calculated.

RESULTS

Compared to adolescents with normal CRF, the ones with low CRF had higher insulin resistance indices (p=0.023) and insulin secretion response (p=0.010), independently of the body mass index z-score.

CONCLUSIONS

Interventions in obese adolescents should focus on the maintenance or improvement of CRF to at least 80% of predicted VO2max. Indeed, this cut-off was significantly related to insulin secretion responses, independently of the adiposity level. A CRF above the proposed cut-off may prevent the development of insulin resistance.

Wide housing space and chronic exercise enhance physical fitness and adipose tissue morphology in rats

The current cages commonly used in animal experiments can prevent rats from engaging in most forms of natural locomotion behaviors. These animals tend to exhibit sedentary habits. Here, we show that a combination of wide housing space and training exercise helps to reduce white adipose mass and to increase brown adipose mass. Thus, this combination is a useful strategy for truly enhancing the physical fitness of captive rats commonly used in exercise-related interventional studies and to maximize their welfare.

Physical activity patterns and metabolic syndrome in Costa Rica

OBJECTIVE

To examine whether total physical activity or activity patterns are associated with metabolic syndrome and its components.

METHODS

Participants include 1994 controls from a case-control study of non-fatal myocardial infarction in Costa Rica (1994-2004). Physical activity was assessed via self-administered questionnaire and patterns were identified using principal components analysis. Metabolic syndrome was assessed via blood samples and anthropometry measurements from in-home study visits. Prevalence ratios (PRs) and 95% confidence intervals (CIs) were calculated using log binomial regression. Adjusted least squares means of metabolic syndrome components were calculated by quintile of total activity and pattern scores.

RESULTS

Four activity patterns were identified: rest/sleep, agricultural, light indoor activity, and manual labor. Total activity was not associated with metabolic syndrome. Metabolic syndrome prevalence was 20% lower in participants with the highest scores on the agricultural job pattern compared to those with the lowest (PR: 0.80, 95% CI: 0.68-0.94). Higher total activity was associated with lower triglycerides and lower HDL cholesterol. Higher scores on each pattern were inversely associated with metabolic syndrome components, particularly waist circumference and fasting blood glucose.

CONCLUSIONS

Patterns or types of physical activity may be more strongly associated with metabolic syndrome and its components than total activity levels.

Consequences of obesity and weight loss: a devil's advocate position

Obesity is associated with multiple negative health consequences and current weight management guidelines recommend all obese persons to lose weight. However, recent evidence suggests that not all obese persons are negatively affected by their weight and that weight loss does not necessarily always improve health. The purpose of this review is not to trivialize the significant health risks associated with obesity, but to discuss subpopulations of obese people who are not adversely affected, or may even benefit from higher adiposity, and in who weight loss per se may not always be the most appropriate recommendation. More specifically, this review will take a devil's advocate position when discussing the consequences of obesity and weight loss for adults with established cardiovascular disease and type 2 diabetes, weight cyclers, metabolically healthy obese adults, youth, older adults and obese individuals who are highly fit.

Physical fitness, overweight and the risk of eating disorders in adolescents. The AVENA and AFINOS studies

What is already known about this subject Eating disorders are among the public health issues facing adolescents. An excess of body fat has been associated with an increased risk of these disorders. The association of physical fitness with eating disorders has not yet been analysed in adolescents. What this study adds This study confirms that the overweight and obesity increase the risk of developing eating disorders. The present study shows that there is an inverse association between physical fitness levels and the risk of eating disorders. This study suggests that physical fitness might attenuate the influence of overweight on the development of eating disorders in adolescents.

BACKGROUND

Eating disorders together with the overweight and obesity are important health concerns in adolescents.

OBJECTIVE

To analyse the individual and combined influence of overweight and physical fitness on the risk of developing eating disorders in Spanish adolescents.

METHODS

The sample consisted of 3571 adolescents (1864 females), aged 13 to 18.5 years, from Spain who participated in the AVENA and AFINOS studies. The risk of eating disorders was evaluated using the SCOFF questionnaire. Body mass index was calculated and the adolescents were classified into two groups: overweight (including obesity) and non-overweight according to Cole's cut-off points. Cardiorespiratory fitness in the AVENA Study was assessed by the 20-m shuttle-run test and the overall physical fitness level was self-reported in the AFINOS Study.

RESULTS

Overweight adolescents had a higher risk of developing eating disorders than non-overweight adolescents (odds ratio [OR] = 4.91, 95% confidence interval [CI]: 3.63-6.61 in the AVENA Study and OR = 2.45, 95% CI: 1.83-3.22 in the AFINOS Study). Also, adolescents with medium and low levels of physical fitness had a higher risk of developing eating disorders (OR = 1.51, 95% CI: 1.05-2.16, and OR = 2.25, 95% CI: 1.60-3.19, respectively, in the AVENA Study, and OR = 1.73, 95% CI: 1.37-2.17, and OR = 4.11 95% CI: 2.98-5.65, respectively, in the AFINOS Study) than adolescents with high levels of physical fitness. In both studies, the combined influence of overweight and physical fitness showed that adolescents with lower levels of physical fitness had an increased risk of developing eating disorders in both non-overweight and overweight groups.

CONCLUSIONS

Physical fitness might attenuate the influence of overweight on the development of eating disorders in adolescents.

Effect of a park-based after-school program on participant obesity-related health outcomes

PURPOSE

The objective of this study was to examine the effect of a structured after-school program housed in a large county parks system on participant health and wellness outcomes.

DESIGN

Longitudinal cohort study over one school year (fall 2011-spring 2012).

SETTING

A total of 23 county parks in Florida.

SUBJECTS

Children ages 5 to 16 (N = 349, 55% non-Hispanic black, 40% Hispanic, mean age 8.9 years).

INTERVENTION

An after-school program called Fit-2-Play that integrates daily standardized physical activity and health and wellness education components.

MEASURES

Preintervention (August/September 2011) and postintervention (May/June 2012) anthropometric, systolic/diastolic blood pressure, fitness, and health and wellness knowledge measurements were collected.

ANALYSIS

Comparison of pre-post outcome measure means were assessed via general linear mixed models for normal-weight (body mass index [BMI] <85th percentile for age and sex) and overweight/obese (BMI ≥85th percentile for age and sex) participants.

RESULTS

The overweight/obese group significantly decreased their mean (1) BMI z score (2.0 to 1.8, p < .01) and (2) subscapular skinfold measurements (19.4 to 17.5 mm, p < .01) and increased (1) mean laps on the Progressive Aerobic Cardiovascular Endurance Run test (10.8 to 12.5, p = .04) and (2) percentage with normal systolic blood pressure (58.1% to 71.0%, p = .03) from pretest to posttest. On average, participants significantly improved their health and wellness knowledge over the school year (p < .01). Normal-weight participants maintained healthy BMI ranges and significantly increased fitness levels.

CONCLUSION

Findings suggest that the Fit-2-Play after-school programs can be a significant resource for combating childhood obesity and instilling positive physical health in children, particularly among ethnic and socioeconomically diverse communities.

Arterial stiffness in obese children: Role of adiposity and physical activity

OBJECTIVE

To explore association of adiposity and physical activity with arterial stiffness and to propose optimal waist circumference cutoffs, corresponding to 90(th) percentile of NHANES (National Health and Nutrition Examination Survey) for Indian children and adolescents.

MATERIALS AND METHODS

Data on weight, height, waist circumference, physical activity and right Carotid artery Intima-Media-Thickness (CIMT), pulse wave velocity (PWV), elasticity modulus (Ep), stiffness index(β), arterial compliance (AC) were assessed in 250 children (72 normal-weight and 178 overweight/obese) aged 6-17 years from Pune city, India. Body composition was measured using Dual energy X-ray absorptiometry.

RESULTS

Total, 37.1% normal-weight and 98.2% overweight/obese children had high adiposity (>95(th) body fat percentile). Positive association of PWV and Ep (r = 0.5) also β(r = 0.25) with BMI (Body Mass Index), waist circumference and body fat (P < 0.05) was observed. Physical activity was inversely associated with PWV (r =-0.2), β(r =-0.13), Ep (r =-0.12) and positively with AC (r = 0.12) (P < 0.05). PWV significantly increased with increasing body fat for each tertile of physical activity (P < 0.05). Regression analysis revealed waist circumference, BMI, body fat and physical activity as independent associates for PWV after adjusting for age (P < 0.05). The cutoff of waist circumference yielding sensitivity and specificity for predicting the risk of high PWV was (-0.43, -0.44) for boys and girls with sensitivity in boys (girls) of 78% (87%) and specificity in boys (girls) 51% (70%). The observed cutoffs are less than the NHANES-III cutoff values of waist circumference for 90(th) percentiles according to age and sex.

CONCLUSION

High adiposity and low physical activity are adversely related to arterial stiffness in Indian children.

Recommendations for promoting physical activity for children and adolescents in Germany. A consensus statement

Increasing physical activity and reduction of sedentary behaviour play important roles in health promotion and prevention of lifestyle-related diseases in children and adolescents. However, the question of how much physical activity is useful for which target group is still a matter of debate. International guidelines (World Health Organization; European Association for the Study of Obesity), which are mainly based on expert opinions, recommend 60 min of physical activity every day. Age- and sex-specific features and regional differences are not taken into account. Therefore, expert consensus recommendations for promoting physical activity of children and adolescents in Germany were developed with special respect to national data, but also with respect to aspects of specific target groups, e.g., children with a lower socio-economic status (SES) or with migration background. They propose 90 min/day of physical activity, or at least 12,000 steps daily. Additionally, lifestyle factors, especially restriction of media consumption, were integrated. The recommendations provide orientation for parents and caregivers, for institutions such as schools and kindergartens as well as for communities and stakeholders.

A community-based exercise intervention transitions metabolically abnormal obese adults to a metabolically healthy obese phenotype

BACKGROUND

Lower habitual physical activity and poor cardiorespiratory fitness are common features of the metabolically abnormal obese (MAO) phenotype that contribute to increased cardiovascular disease risk. The aims of the present study were to determine 1) whether community-based exercise training transitions MAO adults to metabolically healthy, and 2) whether the odds of transition to metabolically healthy were larger for obese individuals who performed higher volumes of exercise and/or experienced greater increases in fitness.

METHODS AND RESULTS

Metabolic syndrome components were measured in 332 adults (190 women, 142 men) before and after a supervised 14-week community-based exercise program designed to reduce cardiometabolic risk factors. Obese (body mass index ≥30 kg · m(2)) adults with two to four metabolic syndrome components were classified as MAO, whereas those with no or one component were classified as metabolically healthy but obese (MHO). After community exercise, 27/68 (40%) MAO individuals (P<0.05) transitioned to metabolically healthy, increasing the total number of MHO persons by 73% (from 37 to 64). Compared with the lowest quartiles of relative energy expenditure and change in fitness, participants in the highest quartiles were 11.6 (95% confidence interval: 2.1-65.4; P<0.05) and 7.5 (95% confidence interval: 1.5-37.5; P<0.05) times more likely to transition from MAO to MHO, respectively.

CONCLUSION

Community-based exercise transitions MAO adults to metabolically healthy. MAO adults who engaged in higher volumes of exercise and experienced the greatest increase in fitness were significantly more likely to become metabolically healthy. Community exercise may be an effective model for primary prevention of cardiovascular disease.

Benefícios da modificação do estilo de vida na síndrome metabólica

INTRODUÇÃO: Os principais fatores de risco para as doenças cardiovasculares hipertensivas e isquêmicas da síndrome metabólica (SM) podem ser favoravelmente modificados pelo estilo de vida (EV). OBJETIVO: Avaliar o efeito de um programa de modificação do estilo de vida sobre os fatores de risco cardiovascular de voluntários com síndrome metabólica (SM). MATERIAIS E MÉTODOS: Ensaio clínico em que oito voluntários (cinco mulheres) com diagnóstico de SM foram submetidos, ao longo de três meses, à intervenção nutricional quinzenal e a um programa de exercício físico, realizado em esteira rolante com intensidade de 65% a 75% da frequência cardíaca máxima, com duração de 30 minutos, três vezes por semana. Após o programa os dados foram comparados pelo teste t de Student. RESULTADOS: Houve redução significativa da pressão arterial sistólica (-7,5%), triglicerídeos (-6,7%) e lipoproteínas de alta densidade (-8%). Além disso, o índice de trabalho cardíaco avaliado em repouso reduziu significativamente (-11%), ao passo que o condicionamento físico expresso pelo trabalho muscular e consumo de oxigênio aumentaram significativamente (29% e 24%, respectivamente). CONCLUSÃO: Até o momento, esses resultados indicam que a mudança nos hábitos alimentares associados à prática regular de exercício físico pode reduzir beneficamente as concentrações de triglicerídeos, bem como a PAS e o DP. Além disso, devido à relevância dos resultados obtidos ao final do programa, acredita-se que a continuidade das atividades propostas neste estudo possa beneficiar outros indivíduos com SM.

A cross-sectional study of low physical fitness, self-rated fitness and psychosocial factors in a sample of Finnish 18- to 64-year-old men

Background

The biological risk factors of inactivity and poor cardiorespiratory fitness are well established. However, risk groups are hard to reach and they may have misperceptions of their need for change. This study explored self-ratings of physical fitness (PF) and the relationship between objectively estimated physical fitness (PFI) and psychosocial factors among Finnish men of working-age.

Methods

Cross-sectional data on 899 Finnish men (aged 18–64) were collected in 2011. Health- related physical fitness was evaluated with a physical fitness index calculated from the results of selected fitness tests. The men were subsequently classified into three groups: low, moderate and high PFI. Psychosocial factors and self-rated fitness were elicited in the questionnaire. The data were analysed with crosstabulations, chi square-test and logistic regression analysis.

Results

One-fifth of the participants had low PFI. Forty-five per cent of the low-fit middle-aged (35–49 years) men self-reported poor PF, while 80 per cent of the younger (18–34 years) low-fit men self-reported moderate or good PF. The health benefits and recommended dose of physical activity were well known in all the PFI categories. The low-fit men were health conscious, but lacked adequate exercise skills, self-efficacy and social support. However, logistic regressions revealed that, in the younger men, likelihood of better knowledge was not related to higher PFI. Among the 50-to-64-year-old men, high PFI was not associated with a higher social support.

Conclusions

Poor exercise skills, self-efficacy and social support were related to low PFI. Physical activity promotion for low-fit men should take into account age differences in the relationship between psychosocial factors and physical fitness. Thus, new and effective ways to establish social support and motivation for physical activity among low-fit men in all working-age groups are needed. Further research is also warranted on whether estimation of PFI could be used as a practical health counselling tool.